EP3078842A1 - Valve assembly - Google Patents

Abstract

Valve arrangement for metering a gaseous fuel in internal combustion engines having a plurality of electromagnetically operable switching valves of a single cross section, wherein the switching valves are designed as poppet valves, the valve assembly is assigned to a combustion chamber and the valve assembly has a nominal cross section for providing a predetermined mass flow, wherein the poppet valves are designed such that a sum of the individual cross sections is at least equal to the nominal cross section, - An effective cross-section due to a valve lift of all poppet valves is equal to the nominal cross section and - the effective cross section is less than or equal to the sum of the individual cross sections.

Description

The present invention relates to a valve assembly according to the preamble of claim 1. From the prior art are various valve assemblies for metering a gaseous fuel in internal combustion engines with a plurality of electromagnetically actuated switching valves of a single cross-section, wherein the switching valves are designed as seat valves, the valve assembly a combustion chamber assigned is and the valve assembly has a nominal cross section for providing a predetermined mass flow known. Such valve arrangements are for example in the WO 2007/036 382 A1 and the US 4,545,345 or the EP 1 888 956 B1 disclosed.

In the prior art come for so-called large gas engines, d. H. in particular for gas engines with an output of preferably at least 500 kW plate valves as so-called Einblasventile for the gaseous fuel used.

Such plate valves have a gas inlet and a gas outlet, wherein between the inlet and outlet a multi-perforated partition plate and a plate-shaped sealing element adapted thereto for closing the openings in the partition plate are arranged. The plate valve thus constructed is actuated by an electromagnetic drive, so that the sealing element is either lifted from the partition plate and thus releases the passages or rests on this and the passages sealingly closes. This structure is chosen in the prior art, since so far only in this way the required large nominal cross-sections of up to 1,500 mm ² can be achieved.

The known from the prior art plate valves have several disadvantages, which are briefly described below.

On the one hand, such plate valves require a high-precision bearing of the sealing element, since a uniform opening of the valve can only be achieved with an absolutely parallel alignment of sealing element and separating plate, and adequate sealing behavior can be achieved with a justifiable leakage.

Moreover, it is considered to be disadvantageous that the plate valves known from the prior art require a comparatively large installation space, since the minimum required base area is determined by the size of the separating or sealing plate used. Such plate valves are due to their structure relatively susceptible to particle entry in the gas stream, since such particles can be deposited in the region of the partition plate and thus the function of the plate valve can be impaired overall. There is no redundancy.

It is the object of the present invention to provide a valve arrangement which does not have the disadvantages known from the prior art, has increased reliability and is more flexible to use. This object is achieved by a valve arrangement having the features of patent claim 1. Advantageous developments are reflected in the dependent claims.

The use of a valve arrangement according to the invention is subject matter of claim 10. A corresponding modular system for constructing the valve arrangements according to the invention is the subject of claim 11.

A valve arrangement according to the invention for metering a gaseous fuel in internal combustion engines having a plurality of electromagnetically operable switching valves of a single cross section, wherein the switching valves are designed as poppet valves, the valve assembly is assigned to a combustion chamber of the internal combustion engine and the valve assembly has a nominal cross section for providing a predetermined mass flow characterized in that the poppet valves are designed such that a sum of the individual cross sections is at least equal to the nominal cross section, an effective cross section due to a valve lift of all poppet valves is equal to the nominal cross section and the effective cross section is less than or equal to the sum of the single cross section.

The present invention is thus based on the fundamental realization that a flexible and at the same time robust valve arrangement can be created by using a plurality of electromagnetically actuated switching valves designed as seat valves, wherein the seat valves are designed such that a sum of the individual cross sections is at least is equal to the nominal cross-section, an arrangement is provided which has at a maximum valve lift in each case necessary for the provision of the predetermined mass flow nominal cross-section. By virtue of the fact that a sum of these individual cross sections can be greater than the required nominal cross section, it is possible with a valve lift of all seat valves that is less than a maximum valve lift to release an effective cross section which corresponds to the nominal cross section, but less than or equal to the sum of the individual cross sections is.

It is achieved in this way that by a duplication of the poppet valves used, a reduction of the necessary valve lift to release the nominal cross section is possible. By reducing the individual cross sections in comparison to a single valve can also take place an optimization of the operating point of the individual seat valves in the force-travel diagram, so that a total of reduced compared to a single valve lifting work can be achieved. A reduced stroke also allows reduced switching times to be achieved.

Advantageously, the switching valves each have their own electromagnetic drive, so that both the valves and the drives are designed to be redundant to each other.

Optimum control of the valve arrangement can be achieved if the switching valves can be actuated jointly or separately, wherein a separate controllability of the switching valves represents a particularly clever design. In fact, with a separate controllability, it is possible for only a single valve or a group of valves to be opened in order to reduce the mass flow provided by the valve arrangement, so that a correspondingly reduced effective cross section is released.

The present invention shows its effect already in a valve arrangement with at least two switching valves, wherein the positive effects in valve arrangements with four switching valves or, for example, six switching valves are even more pronounced.

A particularly compact arrangement can be achieved if the switching valves are arranged in a common housing, wherein the housing has a single feed line and a single outlet for the gaseous fuel. It can be provided in this way a valve assembly, which acts for the user from the outside as a single valve, but by the use of a plurality of switching valves in the interior of the housing has a significantly superior operation.

In terms of production technology, a large number of advantages can be achieved in the manufacture of the present valve arrangement if the switching valves have an identical structure. Through the use of identical parts and the multiplication of the number of valves in a valve arrangement, the number of parts for individual parts can be increased selectively and thus production costs can be reduced.

With regard to the production as well as the leakage, it is advantageous if the switching valves have a substantially rotating part-based structure. By the use of turned parts in the construction of the individual switching valves of the valve assembly can be manufactured with a simple manufacturing process components of high quality in particular low tolerances and thus a significantly reduced leakage of the valve assembly compared to, for example, plate valves, as known from the prior art be guaranteed.

In order to ensure short switching times and at the same time a low wear of the individual switching valves, a maximum valve lift should be less than 5 mm, preferably less than 3 mm. By a small valve lift on the one hand low switching times and on the other hand by the latter resulting shorter acceleration path of a sealing element when closing the valve and reduced wear on the sealing element and valve seat can be achieved.

A preferred valve arrangement has a nominal cross section of about 700 mm ² , wherein the valve assembly is constructed of six switching valves and a valve lift is about 1.5 mm.

A valve assembly according to the invention is preferably used in a large gas engine, this large gas engine is preferably designed for maritime and / or stationary applications and has an output of preferably at least 500 kW.

The present invention further relates to a modular system for constructing valve assemblies for imaging of nominal cross sections of 50 to 1500 mm ² with a plurality of arranged in a common housing, identical, designed as a seat valve electromagnetically actuated switching valves, each having a single cross section and is distinguished characterized in that the individual cross section of the switching valves is less than or equal to the nominal cross section, a number of switching valves used is greater than or equal to a minimum required for the mass flow nominal cross section divided by the individual cross section, a valve lift is adapted to the number of switching valves such that an effective Cross section in a valve lift is equal to the nominal cross section and the number of switching valves used is selected such that a total stroke of all switching valves compared to a single valve at least halved, preferably four elt becomes.

In the context of the present application, the nominal cross section is to be understood as the cross section for ensuring a predetermined mass flow. As a single cross-section is understood a maximum possible cross-section of a valve at full opening thereof. In the present application, the effective cross section represents the sum of the cross sections released in the event of a stroke of all valves of the valve arrangement. Switching valves in the sense of the present application are valves with two switching positions, wherein the valves are preferably designed as normally closed valves. A stroke of the switching valves is limited according to the present application so that a released in a valve lift cross section is less than or equal to the individual cross section of the switching valve, in particular the stroke of the valves is selected such that in a valve assembly, the sum of all released cross sections corresponds to the effective cross section , A maximum valve lift is the valve lift that is necessary for a valve to release the single cross section, ie the maximum possible cross section. In particular, the valve lift may be limited, for example by a mechanical stop to a value smaller than the maximum valve lift and thus limit the released cross-section.

Fig. 1

eine perspektivische Ansicht im Teilschnitt eines ersten Ausführungsbeispiels einer Ventilanordnung mit vier Sitzventilen,

Fig. 2

eine Schnittdarstellung der Ventilanordnung aus Figur 1,

Fig. 3

eine perspektivische Darstellung im Teilschnitt eines zweiten Ausführungsbeispiels einer Ventilanordnung mit zwei Sitzventilen,

Fig. 4

eine perspektivische Darstellung im Teilschnitt eines dritten Ausführungsbeispiels einer Ventilanordnung mit sechs Sitzventilen,

Fig. 5

in einer Kennlinie die Abhängigkeit des Ventilhubesvon der Anzahl der Sitzventile bei identischen Einzelquerschnittenbei gegebenem Nennquerschnitt,

Fig. 6

die Abhängigkeit des Hubes von der Anzahl der Sitzventile bei konstantem Gesamtquerschnitt, die notwendige Hubarbeit für ein Sitzventil sowie die Gesamthubarbeit,

Fig. 7

ein Kennlinienfeld eines elektromagnetischen Antriebs sowie die Arbeitspunkte unterschiedlicher Ausführungsbeispiele und

Fig. 8a-c

als Prinzipskizze in Draufsicht in Fig. 8a ein Einzelventil mit einem ersten Einzelquerschnitt, in Figur 8b vier Sitzventile mit dem Einzelquerschnitt des Ventils aus Figur 8a und in Figur 8c vier Sitzventile mit einem zweiten Einzelquerschnitt, der einem Viertel des ersten Einzelquerschnitts entspricht.

The present invention will be explained in detail below with reference to embodiments with reference to the accompanying figures. Show it:

Fig. 1

1 is a perspective view in partial section of a first embodiment of a valve arrangement with four seat valves,

Fig. 2

a sectional view of the valve assembly FIG. 1 .

Fig. 3

1 is a perspective view in partial section of a second embodiment of a valve arrangement with two seat valves,

Fig. 4

1 is a perspective view in partial section of a third embodiment of a valve arrangement with six seat valves,

Fig. 5

in a characteristic curve the dependence of the valve lift on the number of seat valves with identical individual cross sections for a given nominal cross section,

Fig. 6

the dependence of the stroke on the number of poppet valves with a constant overall cross-section, the necessary lifting work for a poppet valve and the total lifting work,

Fig. 7

a family of characteristics of an electromagnetic drive and the operating points of different embodiments and

Fig. 8a-c

as a schematic diagram in plan view in Fig. 8a a single valve with a first single cross section, in Figure 8b four seat valves with the single cross section of the valve FIG. 8a and in FIG. 8c four seat valves with a second single cross section, which corresponds to a quarter of the first single cross section.

FIG. 1 shows a perspective view of a partial section through a first embodiment of a valve assembly 1 with four switching valves designed as seat valves 3. The valve arrangement 1 has a housing 7, which is essentially formed from a base plate 21 and a cover 8. In the base plate 21, a pressure chamber 19 is formed, which is connected to a supply line 9 for a gaseous fuel. The switching valves 3 are arranged in bores of the base plate 21 such that they can seal the pressure chamber 19 by an outlet 11, which is also formed in the base plate 21, sealing.

In the present embodiment, the four switching valves 3 can be controlled via a common electrical supply line. The individual switching valves 3 have to actuate an electromagnetic drive 5, which is essentially formed of a arranged on a coil carrier magnetic coil, which is arranged to act on an armature of the switching valve 3. In the FIG. 1 shown switching valves 3 are normally closed switching valves 3 and are spring-loaded for this purpose with a compression spring 23 in the closing direction. The switching valves 3 are further designed as so-called conical seat valves, ie that between the pressure chamber 19 and the discharge 11 trained seat 17 of the switching valves 3 and cooperating with the seat 17 anchor 15 at its contact surface have a conical contour.

The embodiment of FIG. 1 is in FIG. 2 shown again in a sectional view. In this sectional view, clearly the arrangement of the switching valves 3 in the base plate 21 can be seen, wherein the switching valves 3 can be screwed into the base plate 21, for example, pressed, welded, soldered or otherwise connected to this. Also, the seat may be fixed in the base plate 21 be and the switching valves 3 can be axially assigned and aligned in the lid 8 fixed.

The arrangement of the switching valves 3 in a common housing 7, the valve assembly 1 is formed as a separately manageable unit, for example via suitable fastening means, such as a flange which is arranged on the base plate 21, a suitable external thread or other suitable fastening means immediately in front of a Combustion chamber, for example, a cylinder of an internal combustion engine can be arranged.

In the in the Figures 1 and 2 illustrated embodiment, the four switching valves are arranged offset in a plan view in each case by 90 °, so that a total of a cylindrical structure of the valve assembly 1 results. But there are also alternative arrangements, for example in series conceivable.

FIG. 3 shows a second embodiment of a valve assembly 1, wherein in the in FIG. 3 illustrated embodiment, two switching valves 3 are arranged in a common housing 7. Since the structure of the valve assembly 1 and the individual switching valves 3 of the respect Figures 1 and 2 In this regard, reference is made to the preceding description.

FIG. 4 shows a third embodiment of a valve assembly 1, in which a total of six switching valves 3 are arranged in a common housing. In a plan view, a first switching valve 3 is arranged centrally, wherein the remaining five switching valves 3 on a circular line around this first switching valve 3 are arranged around. This represents a further arrangement possibility.

In order to avoid unnecessary repetitions, is based on the description of the valve assembly from the Figures 1 and 2 and their components referenced.

To clarify the operation and effects that can be achieved with the valve assemblies 1 according to the present application, the shows FIG. 8 in a schematic representation of three different valve assemblies 1 in a plan view, wherein only the individual cross sections A _{n of} the switching valves 3 are shown and is assumed for simplicity that the respective single cross section A _n for calculating the valve opening necessary for Hubarbeit W _h and the pressure-exposed surface of the Valve corresponds.

In FIG. 8a a single switching valve 3 is shown with a single cross-section A _n . FIG. 8b shows four switching valves 3, wherein each of the switching valves 3 is a single cross-section A _n as the valve FIG. 8a having. In FIG. 8c four switching valves 3 are shown, wherein a sum of the four individual cross sections of the cross section of in FIG. 8a shown switching valve 3, so each of the switching valves has a cross-section A _n / 4.

Under the respective valve arrangements in FIGS. 8a to c Symbols are shown with which the individual arrangements are shown in the characteristics described below.

FIG. 5 shows for a given _nominal cross section A _nominal the dependence of the necessary valve stroke h to obtain an effective cross section A _eff , which corresponds to the _nominal cross section A _nominal depending on a number of switching valves with identical single cross-section A _n . Characteristic curve 101 shows the valve stroke h, wherein characteristic curve 102 for the entire number of the switching valves required lifting work W _h is located.

In the in FIG. 5 1, the abscissa represents the number of switching valves used and the ordinate, on the one hand, the valve lift h (left ordinate) resulting therefrom in one exemplary embodiment and the resulting lifting work W _h (right ordinate).

In order to achieve an effective cross-section A _eff at a predetermined pressure and a nominal cross-section A _nominal , which in the present example is to correspond to the individual cross-section A _{n of} a single switching valve 3, a single switching valve 3 must be used FIG. 8a is shown, are opened to the maximum, ie such that the individual cross-section A _{n is} completely released. For the present consideration, this corresponds to a valve lift h of 8.25 mm.

If instead of a single switching valve 3, four equal size switching valves 3, each with a single cross-section A _{n of} the individual switching valve 3 used, then reduced to achieve the effective cross-section A _eff corresponding to the _nominal cross-section A _nominal valve lift h reduced to one quarter, which in the present embodiment about 2.06 mm corresponds.

The dependence of the valve lift h on the number of switching valves 3 used is shown in characteristic curve 101. From this characteristic it can be seen that the reduction of the valve lift h with increasing number of switching valves used 3 shows a lesser effect, wherein, as can be seen from characteristic curve 102, the total necessary lifting work Wh for opening the valve arrangement 1 remains constant.

This results from the fact that the lifting work W _h , calculated from the force necessary to open the valve assembly multiplied by the necessary to achieve the effective cross section A _eff valve h at a quadruple the pressure-exposed valve surface while maintaining the necessary valve lift h remains the same.

In FIG. 6 is the diagram of the dependence of the valve lift h - again assuming a constant nominal cross section A _nominal valve assembly 1 - of the number of switching valves used 3 shown, wherein the sum of the individual cross sections A _{n of} the switching valves used 3 the individual cross section A _{n of} the individual switching valve. 3 out FIG. 8a or the nominal cross section A _nominal corresponds. In the diagram in FIG. 6 shows the abscissa, the number of switching valves used 3, wherein on the left ordinate the valve lift h and the right ordinate the necessary lifting work W _{h is} plotted. Characteristic curve 103 shows the valve stroke h, characteristic curve 104 the total necessary lifting work W _tot for all switching valves 3 of the valve arrangement 1 and characteristic curve 105 the necessary lifting work W _h for opening a single switching valve 3.

On the stroke characteristic 103 in FIG. 6 are the ones in the FIGS. 8a and 8c illustrated situations, ie, the stroke when using a single switching valve 3 with a single cross-section A _n and four switching valves 3 whose individual cross sections correspond in total to the single cross-section A _{n of} the individual valve.

As can be seen from characteristic curve 103, in such a procedure, the necessary valve lift h can be achieved in order to achieve an effective cross-section A _eff , which corresponds to the _nominal cross-section A _nominal , in comparison to FIG FIG. 5 only halved. At the same time, however, the total necessary lifting work W _{tot can} also be halved. The reduction of the lifting work W _h results from the fact that with the same pressure-exposed surface of the valve assembly 1 and simultaneous halving of the valve lift h and the corresponding necessary lifting work W _{h is} halved.

The reduction of the valve lift h to one-half with a fourfold increase in the number of valves with the same total cross-sectional area results from the fact that a valve diameter in the calculation of the cross-sectional area is square, in a calculation of the released cross-sectional valve lift but only linearly. Consequently, with a generally constant effective cross-sectional area A _eff and a quadrupling of the number of valves, both the necessary valve lift h and the necessary lifting work can be halved.

In FIG. 7 is a characteristic of an electromagnetic drive shown, the three situations off FIG. 8 are entered in the characteristic field. The abscissa shows in the in FIG. 7 represented diagram the valve lift h, wherein the ordinate in the respective operating point achievable force is plotted in Newton. Illustrative linear force core lines are shown for magnets with the following magnetic flux: characteristic 106 with 1000AW, characteristic 107 with 800AW, characteristic 108 with 800AW, characteristic 109 with 400AW and characteristic 110 with 200AW. By a variation of the single cross section A _n for a given nominal cross-section A _nominal , a shift of the operating point of the individual switching valves 3 can be achieved on the characteristic marked 111.

As FIG. 7 can be seen, can be done by a multiplication of the switching valves 3 used in a valve assembly 1 and a suitable adjustment of the individual cross section A _{n of} the switching valves 3, an adjustment of the operating point of the electromagnetic drive.

Overall, according to the present application, not only an optimization in terms of mechanical properties (leakage, redundancy, durability), but also in terms of electrical properties. Overall, a significant cost reduction in the manufacture of the valve assembly can be achieved by the use of identical parts, as well as the increase in the numbers of these common parts.

LIST OF REFERENCE NUMBERS

1

valve assembly

3

switching valves

5

electromagnetic drive

7

casing

8th

cover

9

supply

11

derivation

13

Electrical supply

15

anchor

17

Seat

19

pressure chamber

21

baseplate

23

compression spring

101-105

characteristics

111

Kennlinei

A _n

Single cross section

A _nominal

Nominal cross section

A _eff

effective cross section

H

valve

W _h

lifting work

W _ges

Gesamthubarbeit

Claims (11)

Valve arrangement (1) for metering a gaseous fuel in internal combustion engines having a plurality of electromagnetically operable switching valves (3) of a single cross-section (A _n ), wherein the switching valves (3) are designed as poppet valves, the valve assembly (1) is assigned to a combustion chamber and the valve assembly (1) has a nominal cross-section (A _nenn ) for providing a predetermined mass flow, characterized in that the poppet valves are designed such that a sum of the individual cross sections (A _n ) is at least equal to the nominal cross section (A _nenn ), - an effective cross section (A _eff ) due to a valve lift of all poppet valves is equal to the nominal cross section (A _nenn ) and - The effective cross section (A _eff ) is less than or equal to the sum of the individual cross sections (A _n ). Valve arrangement (1) according to claim 1,
characterized in that the switching valves (3) each have their own electromagnetic drive (5). Valve arrangement (1) according to claim 2,
characterized in that the switching valves (3) are jointly or separately controllable. Valve arrangement (1) according to one of the preceding claims,
characterized in that the valve arrangement (1) has at least two, preferably at least four switching valves (3). Valve arrangement (1) according to one of the preceding claims,
characterized in that the switching valves (3) in a common housing (7) are arranged, wherein the housing (7) has a supply line (9) and a discharge line (11) for the gaseous fuel. Valve arrangement (1) according to one of the preceding claims,
characterized in that the switching valves (3) have an identical structure. Valve arrangement (1) according to one of the preceding claims,
characterized in that the switching valves (3) have a substantially drehteilbasierten structure. Valve arrangement (1) according to one of the preceding claims,
characterized in that a maximum valve lift (h) is less than 5 mm, preferably less than 3 mm. A valve assembly (1) according to one of the preceding claims, having a nominal cross-section (A _nom) of 700 mm ² and 6, switching valves, wherein a valve lift (h) is 1.5 mm. Use of a valve arrangement (1) according to one of the preceding claims in a large gas engine, preferably for maritime and / or stationary applications with a power of preferably at least 500 kW. Modular system for the construction of valve assemblies (1) for imaging of nominal cross-sections (A _nominal) of 50 mm ² to 1500 mm ² with a plurality of in a common housing (7) arranged, identical, formed as a seat valve electromagnetically operated switching valves (3), with each a single cross section (A _n ),
characterized in that - the individual cross section (A _n ) is less than or equal to the nominal cross section (A _nenn ), - a number of the switching valves (3) used is greater than or equal to a least necessary for the mass flow nominal cross-section (A _nominal) divided by the single cross-section (A _n), - a valve lift (h) in such a way the number of switching valves (3) is adapted in that an effective cross section (A _eff ) at a valve lift (h) is equal to the nominal cross section (A _nenn ) and - The number of switching valves used (3) is selected such that a total lifting work (W _ges ) all switching valves (3) compared to a single valve at least halved, preferably quartered.

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